$('_').siblings().css({'_':'_'})

.removeClass
.addClass
.toggleClass

 Add Content after an element close
.append

Add Content before an element open tag
.prepend


change an elements ID Name
.attr('attr-new-id', 'new-id')
.attr('id', 'prop-new-id')'

Execute code on a click event:
$(#a-button').on('click,fuction(){
cosole.log('button clicked');
})'

$(#a-button').click(fuction(){
cosole.log('button clicked');
});

Form Element Selectors
:checkbox
:input
:focus
:selected
:submit

The .val() method allows you get or set the value entered into a form element:
// Get the text string currently entered into the input:
$('input:text').val();
// Set a new value for the input by passing in a string:
$('input:text').val('A new value');
// Clear out an input by passing empty quotes into .val():
$('input:text').val('');

Email validation
<form id="my-form">
   <input type="email" id="my-text-input" />
   <input type="submit" />
</form>

$('#my-form').on('submit', function(event) {
   event.preventDefault();
   if ( $('#my-text-input').val() == '' ) {
      alert('You missed the field.');
   } else {
      alert('Thanks for filling the field!');
   }
});

   $('.add-to-cart').click('button', function(event) {
    event.preventDefault();

    var cartCount = parseInt($('.count').html(), 10);

    $('.count').html(cartCount +=1);

    // .count = (.count + cartCount);
      // $('.add-to-cart').add(cartCount += 1);